Currently, 3rd generation cellular communication systems are being rolled out to further enhance the communication services provided to mobile phone users. The most widely adopted 3rd generation communication systems are based on Code Division Multiple Access (CDMA) and Frequency Division Duplex (FDD) or Time Division Duplex (TDD) technology. In CDMA systems, user separation is obtained by allocating different spreading and/or scrambling codes to different users on the same carrier frequency and in the same time intervals. This is in contrast to time division multiple access (TDMA) systems, where user separation is achieved by assigning different time slots to different users.
In addition, TDD provides for the same carrier frequency to be used for both uplink transmissions, i.e. transmissions from the mobile wireless communication unit (often referred to as wireless subscriber communication unit) to the communication infrastructure via a wireless serving base station and downlink transmissions, i.e. transmissions from the communication infrastructure to the mobile wireless communication unit via a serving base station. In TDD, the carrier frequency is subdivided in the time domain into a series of timeslots. The single carrier frequency is assigned to uplink transmissions during some timeslots and to downlink transmissions during other timeslots. An example of a communication system using this principle is the Universal Mobile Telecommunication System (UMTS). Further description of CDMA, and specifically of the Wideband CDMA (WCDMA) mode of UMTS, can be found in ‘WCDMA for UMTS’, Harri Holma (editor), Antti Toskala (Editor), Wiley & Sons, 2001, ISBN 0471486876.
Typically within a UMTS network, each serving base station, referred to as a NodeB, is operably coupled to a base station controller, referred to as a radio network controller (RNC), via a backhaul link. It is known for a communication capacity of such a backhaul link to be limited to less than, or equal to, that of the air-interface between the base station and wireless subscriber communication units. This situation is common in many Operator networks during early stages of a network roll-out, for example when a number of active wireless subscriber communication units do not justify an expensive high bandwidth backhaul.
Typically, within 3rd generation cellular communication systems, the backhaul link carries user plane traffic of two types:                just-in-time (JIT) traffic (for example, in 3gpp this would be Forward Access Channel (FACH), Downlink Shared Channel (DSCH), Dedicated Channel (DCH) that has to arrive at the base station within a time window for it to be transmitted over the air-interface, else it is discarded. The just-in-time traffic is scheduled on the air-interface by the base station controller.        other traffic (e.g. non just-in-time, NJIT) that should be sent to the base station as soon as possible, but will not be discarded according to the time of arrival (for example, in 3GPP this would be High Speed Downlink Shared Channel (HS-DSCH)). NJIT traffic is scheduled on the air-interface by the base station.        
A problem faced, when implementing such a system, is how to share the available backhaul link bandwidth between these two types of traffic to meet the goals of:                The bandwidth being shared according to an intended ratio.        The JIT traffic should reach the base station within a desired time window.        The link should be optimally utilised.        
It is known to establish a bandwidth sharing ratio, whereby each traffic type is allocated a predefined proportion of the available backhaul link bandwidth. In this manner, each traffic type is assured a certain amount of bandwidth across the communication link. However, when there is a low amount of traffic for one of the traffic types, not all of the allocated bandwidth for that traffic type will be used, even if the other traffic type has greater demand than its allocation, and as such valuable bandwidth resource is wasted.
This is particularly undesirable in a situation where a capacity of the backhaul link is limited to less than, or equal to, that of the air-interface, since it may result in not only the backhaul link bandwidth not being fully utilised, but also the air-interface bandwidth not being fully utilised.
Consequently, current techniques are suboptimal. Hence, an improved mechanism to address the problem of managing backhaul resources within a cellular network would be advantageous.